Cloth

ABSTRACT

A fabric for clothes that has a decreased flow resistance shows a compression ratio of a micro-area in the fabric surface, on the surface side opposite to a body, of from 8 to 90%, and has streaky protruded portions on the surface side opposite to body. The protruded portions preferably have a width of 100 to 2,500 mm, and a height of 30 to 300% of the width of the protruded portions. Moreover, the protruded portions are preferably wavy, streaky ones in one direction on the surface side opposite to a body.

FIELD OF THE INVENTION

The present invention relates to a fabric that shows a decreasedresistance to a flow of a fluid such as water or air.

BACKGROUND ART

In the field of sportswear for racing, in which athletes struggleagainst each other to achieve a higher speed, various attempts have beenmade to decrease the resistance of the fabric itself to a flow of afluid such as water and air, and the resistance of sportswear, etc., toa flow of a fluid by the design of the sportswear, etc. Making a fabricsurface smooth has heretofore been known as means for decreasing theresistance of the fabric itself to water and air. For example, for afabric used for racing swimwear, or the like, typical examples of themethod of decreasing resistance to fluid such as water and air bysmoothing the fabric surface include a method comprising pressing thefabric with a heat calendar roll or a hot plate, and a method comprisinglaminating a film, etc., to the fabric.

For example, Japanese Unexamined Patent Publication (Kokai) No. 7-279038describes a fabric that is coated with a metallic thin film layer andsubjected to resin treatment in addition to pressing with a heatcalendar roll and that shows a very small standard deviation of surfaceroughness.

Japanese Unexamined Patent Publication (Kokai) Nos. 3-137203, 3-137204,7-243104, 8-246209, 9-31721, 11-152610, and the like, describe a fabricthe fluid resistance of which is decreased by providing the fabric withgrooves and projections in a direction parallel to a fluid flow so thatthe fluid flow is made smooth.

Furthermore, Japanese Patent Publication No. 2711807, JapaneseUnexamined Patent Publication (Kokai) No. 8-311751, Japanese PatentPublication No. 3283404, and the like, describe a method that combines aprocedure of making a fabric water-repellent and a procedure of makingthe fabric non-water repellent so that the eddy resistance between fluidand the fabric is decreased.

Although all of the above conventional technologies consider the actionof a fabric on a fluid, they do not consider the action of fluid exertedon a fabric, that is, they do not consider deformation of a fabriccaused by fluid pressure. The following fabric has never beenconsidered: a fabric designed to decrease a fluid resistance while aflow velocity of fluid in racing, in which athletes struggle againsteach other to get a higher speed, namely, a fabric deformation caused byfluid under a considerable pressure, is taken into consideration.

Furthermore, a method of decreasing resistance of fluid by making thefluid smooth in the direction parallel to the fluid flow has been known.However, when the fabric is provided with linear streaky unevennessparallel to the fluid flow, the size of an eddy generated increasesbecause the path of the fluid proceeding on the fabric increases.Therefore, apprehensions about an increase in the fluid resistance arefeared. The following fabric has never been found: a fabric designed todecrease fluid resistance that is exerted thereto in directions otherthan the fluid flow direction while the fabric is assumed to be actuallyworn and while wearer's motion in considerably random directions duringwearer's practicing athletic sports, for example, wearer's hand motionduring crawling in swimming is taken into consideration.

DISCLOSURE OF THE INVENTION

A problem to be solved by the present invention is to obtain a fabrichaving a still lower resistance, to fluid such as air and water, thanfabrics obtained by conventional technologies. An object of the presentinvention is to provide a fabric that is designed while deformation ofthe fabric caused by fluid, and wearer's body motions in considerablyrandom directions during wearer's body movements, are taken intoconsideration.

As a result of carrying out investigations to solve the above problems,the present inventors have discovered that the compression ratio whencompressing a micro-area in a surface of a fabric and the surfaceroughness of the fabric are related to the deformation thereof caused byfluid such as water and air, and the present invention has thus beenachieved.

That is, the present invention is explained below.

1. A fabric for clothes showing a compression ratio of a micro-area inthe fabric surface on the surface side opposite to a body of from 8 to90%, and having streaky protruded portions on the surface side oppositeto body.

2. The fabric according to 1 mentioned above, wherein the protrudedportions have a width of 100 to 2,500 μm, and a height of 30 to 300% ofthe width of the protruded portions.

3. The fabric according to 1 mentioned above, wherein the fabric has, onthe surface side opposite to body, wavy, streaky protruded portions inone direction.

4. The fabric according to 3 mentioned above, wherein protruded portionsin the wavy, streaky protruded portions have a width of 100 to 2,500 μm,a height of 15 to 300% of the width of the protruded portions, a cycleof waviness of 2,000 to 20,000 μm, and a width of the waviness of 5 to50% of the cycle of waviness.

5. The fabric according to any one of 1 to 4 mentioned above, whereinthe streaky protruded portion has micro-unevenness having a depth of 80%or less of the height of the protruded portion in the direction verticalto the streaky protruded portion.

6. The fabric according to any one of 1 to 5 mentioned above, whereinthe average deviation of a surface roughness in the direction parallelto the streaky protruded portions is 5 μm or less, and the averagedeviation of a surface roughness in the direction vertical to thestreaky protruded portions is 8 μm or less.

7. The fabric according to any one of 1 to 6 mentioned above, whereinthe fabric is composed of a polyester yarn and an elastic yarn.

8. The fabric according to 7 mentioned above, wherein the fabric is ajacquard knitted fabric.

9. The fabric according to any one of 1 to 7 mentioned above, whereinthe fabric has a surface layer of an elastic layer on the surface side,opposite to a body, of the fabric.

10. Sportswear for racing formed, in at least a portion thereof, out ofthe fabric according to any one of 1 to 9 mentioned above.

11. Swimwear formed, in at least a portion thereof, out of the fabricaccording to any one of 1 to 9 mentioned above.

12. The swimwear according to 11 mentioned above, wherein the fabric hasstreaky protruded portions arranged in the longitudinal direction of ahuman body.

In the present invention, the surface side, opposite to the body, of afabric signifies a surface opposite to the wearer's body when theclothes are worn, that is, it signifies a surface side that is contactedwith an external environment. For example, for swimwear, the surfaceside, opposite to the body, is the surface in contact with a fluid suchas water.

The present invention is explained below in detail.

In general, when the surface of a fabric is smooth, that is, when thesurface roughness of a fabric is small, the fluid resistance of thesurface of the fabric is decreased. Moreover, the effect of decreasingthe fluid resistance is enhanced by making the fluid flow smooth byproviding grooves and projections to the fabric in the directionparallel to the fluid flow. However, the present inventors have foundthat in order to decrease the fluid resistance, the compression ratio ofmicro-area in the fabric surface is a very important factor in additionto the effect of decreasing the surface roughness of the fabric and thesmooth flow effect obtained by providing grooves and projections.

When an object proceeds in the water or the air, eddy flows are producedaround the periphery thereof, and the process thereof is hindered.However, the eddy flows are decreased and, as a result, the fluidresistance is decreased, by compression deformation of the fabric.Although the mechanism of decreasing the eddy flows is not necessarilydefinite, it is estimated that the dynamic behavior of fabric surfacerepeating compression deformation-recovery suppresses the growth of eddyflows. Because the easiness of forming micro-deformations of the fabricnear the surface thereof particularly greatly influences the dynamicbehavior, a fabric having a larger compression ratio of a micro-area inthe fabric surface exhibits a greater effect of decreasing eddy flows.

The fabric of the present invention must therefore have a compressionratio of micro-area in the fabric surface on the surface side oppositeto body of 8 to 90%.

In general, a fabric for swimwear, for example, a knitted fabric such asa two-way tricot knitted fabric formed out of a polyester yarn and aspandex yarn, or a knitted or woven fabric provided with grooves orprojections to obtain a smooth flow effect has a compression ratio ofmicro-area in the fabric surface of less than 8%. When the compressionratio of micro-area in the fabric surface is less than 8%, deformationunder pressure, namely, deformation of a fabric caused by fluid isinsufficient. As a result, the effect of decreasing a fluid resistancecaused by deformation is small. When the compression ratio of micro-areain the fabric surface exceeds 90%, the surface deformation becomesexcessively large, and the durability of the fabric becomes poor.Moreover, when the fabric has a laminated resin film, as will bedescribed later, the fabric has strong tucking properties for some filmmaterials, and the handleability of the fabric during wearing sometimesbecomes poor.

The fabric of the present invention shows a large compression ratio ofmicro-area in the fabric surface, and a large fabric surface deformationcaused by fluid pressure. As a result, the fabric displays the effect ofdecreasing a fluid resistance not only in the flowing direction of fluidbut also in all directions in accordance with the motion of the wearer'sbody.

Examples of the effective method of making the compression ratio ofmicro-area in the fabric surface fall in a range of 8 to 90% include amethod of forming the fabric surface out of a soft, elastic fiber, amethod of covering the fabric surface with a soft elastic resin, and amethod of making the fabric surface have a special, compressible shape.These methods can be used singly or in combination. As will be describedlater, even for a conventional two-way knitted fabric, the compressionratio of micro-area in the fabric surface of 8 to 90% can be achievedwhen the fabric has an adequately compressible uneven shape. Moreover,for a fabric that has a surface formed out of an elastic material, thecompression ratio can be achieved even when the uneven shape isrelatively small.

The fabric of the present invention has streaky protruded portions onthe surface side opposite to body of the fabric. When the fabric hasstreaky protruded portions, a smooth flow effect can be obtained and acompressive deformation near the fabric surface is likely take place.When the fabric is used for clothes, the streaky protruded portions arepreferably arranged on the surface side of the fabric, opposite to abody, in the longitudinal direction of a human body. That is, making thestreaky protrusions approximately parallel to the fluid flow directionis desirable because the fluid resistance becomes a minimum. Althoughthe shape of the streaky protruded portions differs depending on theelasticity of a material forming the fabric and the surface shape of thefabric, the width is preferably from 100 to 2,500 μm, and morepreferably from 100 to 1,500 μm.

In order to increase the compression ratio of micro-area in the fabricsurface, the area of the protruded portions is 50% or less of the fabricarea, more preferably 30% or less. In addition, the area of theprotruded portions herein signifies an area of the widths of theprotruded portions in the measured plane described below.

As explained later, the shape of protruded portions is measured with athree-dimensional shape determination system LC 2400 (manufactured bySIGMA KOKI CO., LTD.).

The width of the protruded portions is explained below. Data obtained bymeasurements is converted to EXCEL, and the average value of vertexes ofthe streaky protruded portions is obtained. The protruded portions arevirtually cut with a plane 30% apart from the average value of thevertexes. The width of the protruded portions designates the average ofthe widths of the virtually cut out protruded portions. The height ofthe protruded portions signifies a distance from the plane to theaverage of the most recessed streaky portions.

When the protruded portions have a width of 2,500 μm or less, the effectof the protruded portions is effectively displayed because the areasuffering a fluid resistance is not excessively large and is suitable.As a result, the deformation caused by compression is sufficient, andthe effect of decreasing a fluid resistance becomes high in accordancewith the deformation. A compression deformation is likely to take placewhen the protruded portions have a small width. However, when the widthis extremely small, the effect of decreasing a fluid resistance islessened because the deformation amount becomes very small. The lowerlimit of a width of the protruded portions is therefore preferably 100μm.

In order to cause an effective deformation by compression, the height ofthe protruded portions is preferably from 30 to 300% of the width of theprotruded portions, and more preferably from 60 to 250% of thereof. Theabsolute value of the height of the protruded portions is preferably1,000 μm or less in view of a surface roughness to be explained later.When the height of the protruded portions is in the above range, thecompression ratio of the micro-area in the fabric surface can be made tofall in the range of the invention regardless of the type of the fabricmaterial.

In the present invention, streaky protruded portions signify not onlystraight linear ones but also curved ones, curved ones with waves,dotted ones, and the like. For dotted protruded portions, the size, thespace, and the like, of the dots are not restricted. For example, yarnsarranged in rib shape on a knitted or woven fabric are also included.Accordingly, a method of forming the above micro-unevenness with ajacquard knitting or weaving machine is appropriately used.

Although the space of the streaky protruded portions is not specificallylimited, the space is preferably from 500 to 5,000 μm, and morepreferably from 500 to 3,000 μm. When the space is in the above range,the smooth flow effect is effectively displayed. The space of theprotruded portions designates an average of a distance (interval)between a line bisecting the width of a protruded portion (streak of theprotruded portion) and a line bisecting the width of an adjacentprotruded portion (streak of the protruded portion). There is nospecific limitation on the slope between a protruded portion and arecessed portion. The cross section may be trapezoidal, semicircular,and the like. When the protruded portions and the recessed portions aretrapezoidal, the width of a protruded portion and that of a recessedportion are preferably from 20 to 40% of the space between the recessedportion and the protruded portion.

The fabric of the invention preferably has streaky protruded portionshaving waviness on direction, on the surface side opposite to body,because the effect of decreasing a fluid resistance further increases.The waviness herein designates that the streaky protruded portions formcorrugations in the horizontal direction. It has already been known thatthe streaky unevenness along a fluid flow on the surface acceleratessmoothness of the fluid flow, and the fluid resistance is decreased.However, the present inventors have found that wavy, streaky protrudedportions produce a more marked effect of decreasing a fluid resistancethan straight, streaky protruded portions.

The mechanism of decreasing a fluid resistance is not necessarilydefinite, but is explained below. For straight, streaky protrudedportions, the path of a fluid proceeding on the fabric is long; as aresult the size of generated eddies increases to increase the fluidresistance. However, when the streaky protruded portions are made wavy,the fluid hardly proceeds on the streaky unevenness, and the size of theeddies thus produced decreases. Because the fluid resistance is known tobe proportional to the square of the size of the eddies thus generated,reduction of the size of the eddies accelerates lowering the flowresistance. Moreover, when a micro-uneven surface formed by formingwaviness in the streaky protruded portions is compressed by a fluidflow, variations in the directions of the fluid flow are likely to beinduced in comparison with a fluid flow without waviness therein. As aresult, the microcompression of the surface can be increased.

The wavy, streaky protruded portions preferably have the followingdimensions: a width of the protruded portions of from 100 to 2,500 μm; aheight of the protruded portions of from 15 to 300% of the width of theprotruded portions; a cycle of waviness of from 2,000 to 20,000 μm; anda width of waviness of from 5 to 50% of the cycle of waviness. The spaceof the streaky protruded portions is preferably from 300 to 2,500 μm,and more preferably from 500 to 2,000 μm.

When the streaky protruded portions have no waviness, the height of theprotruded portions is preferably from 30 to 300% of the width of theprotruded portions. On the other hand, when the streaky protrudedportions have waviness, the protruded portions the height of which isfrom 15 to 300% of the width thereof can display the effect ofdecreasing a fluid resistance. The effect is produced because the sizeof generated eddies is decreased in comparison with the streakyprotruded portions without waviness, as explained above.

The cycle of waviness designates the length of a repeating unit of thewaviness in the longitudinal direction of the waves. When the cycle ofwaviness is in the above range, the protruded portions fully display theeffect of decreasing the size of generated eddies.

The width of waviness is the amplitude of the waviness. The width is anaverage of a maximum amplitude in the width direction of the midpoint ofthe width of the streaky protruded portions. When the amplitude of thewaviness is in the above range, the effect of waviness is effectivelydisplayed, and the streaky protruded portions produce a marked effect ofdecreasing a fluid resistance in the direction parallel to fluid flows.In addition, the cycle and width of waviness are not necessarilyrequired to be constant. The cycle and width may vary, and variouscycles and widths may be present in the fabric in a mixture.

The fabric of the invention preferably has a micro-unevenness the depthof which is 80% or less of the height of the protruded portion in thevertical direction of the streaky protruded portion, namely, in theheight direction thereof, because the effect of decreasing a flowresistance can be further enhanced. In this case, the streaky protrudedportions are still more preferred when they are wavy, streaky protrudedportions. When the fabric has microprotruded portions having a depth of80% or less of the height of a streaky protruded portion in thedirection vertical to the streaky one, namely, in the direction makingan angle of approximately 80 to 100 degrees, the fabric achieves afurther enhanced effect of decreasing a flow resistance in comparisonwith a fabric having a streaky protruded portion in one direction alone.

That the fabric has a micro-unevenness having a depth of 80% or less ofthe height of a streaky protruded portion in the direction vertical tothe streaky one signifies (in other words) that the height of theprotruded portion in the streaky one varies in the longitudinaldirection. A depth of micro-unevenness signifies a difference between amaximum value and a minimum value of a height or the protruded portion,namely, a variation width of a protruded portion height. A depth ofmicro-unevenness is more preferably from 20 to 80% of the height of theprotruded portion. Moreover, the following are preferred:micro-unevenness is cyclically present; the cycle of micro-unevenness,namely, a distance from a point where the height of the streakyprotruded portion becomes minimum to a point where the height thereofsubsequently becomes minimum is from 80 to 200% of a space of streakyprotruded portions, namely, from 80 to 200% of a distance from thestreaky protruded portion to the adjacent streaky protruded portion.

As explained above, the mechanism of decreasing a fluid resistance byproviding unevenness in the two directions is not necessarily definite.However, the mechanism is explained below. For the fabric havingprotruded portions in one direction alone, eddies are produced in arecessed portion between two protruded portions adjacent to each other,when fluid flows in the direction vertical to the protruded portions. Afluid resistance therefore increases in comparison with a fabric havinga smooth surface. In contrast to the above case, a fabric having streakyunevenness in two directions is inferred to manifest a smooth floweffect on a water flow in each direction to enhance the effect ofdecreasing a flow resistance. In addition to the above inference, thefollowing is inferred. When a fabric is provided with streaky unevennessin the two directions, the protruded portions are likely to be deformedby fluid, and a decrease in the fluid resistance is accelerated by thedeformation in comparison with a fabric having a streaky unevenness inone direction.

Examples of an appropriate method of providing a fabric with streakyprotruded portions include a method comprising preparing a woven orknitted fabric, or the like, with a jacquard machine so that an unevenshape is imparted, a method comprising partially stacking part of theyarn of a knitted fabric such as a smooth knitted fabric or ahalf-tricot knitted fabric so that protruded portions are provided; anda method comprising forming an uneven pattern on a fabric with an embossroll having a carved pattern. Although the embossing temperature differsdepending on a material, the embossing temperature of the mixed knittedfabric of a polyester and a polyurethane is preferably from 160 to 180°C. Moreover, for a fabric having a laminated elastic layer to bedescribed later, a method of imparting protruded portions to a fabricafter the lamination with an emboss roll having a curved uneven pattern.For a urethane resin, the embossing temperature is preferably from 120to 150° C., because the compression properties of the micro-area in thefabric surface are not changed with heat. A method comprising preparingan elastic layer composed of a film of a resin such as a urethane resinwith a releasing paper having an uneven pattern, and sticking theelastic layer to a gray fabric by lamination, or the like proceduremakes the film surface softer. The fabric subsequent to lamination isvery preferred because the fabric shows a large compression ratio ofmicro-area in the fabric surface.

When the surface roughness of the fabric is excessively large, the fluidresistance on the fabric surface is likely to increase due to a largesurface roughness. In order to decrease the fluid resistance on thefabric surface, the average deviation of the surface roughness on thefabric surface is desirably 5 μm or less in the direction parallel tothe streaky protruded portions, and the average deviation of the surfaceroughness is desirably 8 μm or less in the direction vertical to thestreaky protruded portions.

Because fluid mainly flows in the longitudinal direction of a human bodyduring wearing, a direction parallel to the streaky protruded portionsbecomes the longitudinal direction of the clothes. The surface roughnessin this direction is desirably small. In order to make the surfaceroughness fall in the preferred range, protruded portions having aheight of 100 to 1,000 μm are preferably formed by weaving or knittingstitch, laminating, embossing, or the like procedure. When the tip of aprotruded portion is smoothed while the protruded portion has aprotruded streak by calendaring, the fabric has a marked effect ofdecreasing fluid resistance. However, in order to maintain apredetermined compression ratio of micro-area in the fabric surface,attention must be paid not to excessively heat the fabric. A method ofproviding a recessed portion by partially drawing part of the yarnduring knitting, or a method of providing a recessed portion with deepembossing is not preferred because the surface roughness increases toincrease the fluid resistance.

The average deviation of a surface roughness is determined by thefollowing procedure: using a surface tester (trade name of KES-FB4,manufactured by Kato Tech Co., Ltd.), a contact probe 5 mm wide composedof a piano wire 0.5 mm in diameter is press contacted with a sample witha weight of 5 gf to which a uniaxial tension of 29.4 cN is applied, andmeasurements are made while the sample is being horizontally moved for 2cm at a constant speed of 0.1 cm/sec.

The average deviation of surface roughness (SMD) is represented by theformula (1): $\begin{matrix}{{SMD} = {\left( {1/x} \right) \times {\int_{0}^{x}{{T_{X} - T_{A}}}}}} & (1)\end{matrix}$wherein x is a position, T_(x) is a thickness (measured by the contactprobe) at x of the sample, and T_(A) is an average of T.

The fabric of the invention preferably has a surface layer of an elasticlayer on the surface side opposite to body. The elastic layer preferablyshows a compression ratio of a micro-area in the fabric surface of 20 to95%. When the compression ratio of micro-area in the fabric surface ofthe elastic layer is from 20 to 95%, a fabric having the elastic layerformed by lamination can be made to show a compression ratio ofmicro-area in the fabric surface of 8 to 90%. Moreover, the thickness ofthe elastic layer is preferably from 30 to 500 μm, and more preferablyfrom 300 to 500 μm.

A resin film showing a surface compression ratio of a resin (filmthickness of 300 μm) of 20 to 95% is preferred as an elastic layer.Although there is no specific restriction on the type of a resin formingthe elastic layer, a polyurethane resin, an acrylate resin, and the likeare appropriately used.

A fabric can be made to show a compression ratio of micro-area in thefabric surface of 8 to 90% by preparing the fabric with lamination of anelastic layer. For physical properties of the fabric prepared bylamination of an elastic layer composed of a resin film, the tenacity at80% elongation determined by the following procedure is preferably 2.9 Nor less: a test piece 2.5 cm wide of the sample is stretched with achuck-to-chuck distance of 10 cm at a pulling speed of 300 mm/min. Whenthe above tenacity is 2.9 N or less, the stretchability of the fabric isnot hindered.

There is no specific limitation on a yarn forming the fabric in thepresent invention, and any freely selected yarn can be used. Examples ofthe yarn include a multifilaments yarn of a polyester such as apoly(ethylene terephthalate), a poly(trimethylene terephthalate) and apoly(butylene terephthalate), a polyamide multifilaments yarn, apolypropylene multifilaments yarn and a polyurethane multifilamentsyarn. One type of filaments yarn or various types of filaments yarns canbe employed.

Although there is no specific limitation on a total size and a singlefilament size of the yarn, a total size of 33 to 167 dtex, and a singlefilament size of 0.5 to 5 dtex are preferred. There is no specificrestriction on a cross-sectional shape of the yarn, and a freelyselected shape is employed. A yarn having a circular cross-section, atriangular cross-section, a W-shaped cross-section, a hollowcross-section, or the like cross-section is preferred.

A knitted fabric or a woven fabric may be used as the fabric. However,when the fabric is used for sportswear, a knitted fabric or a wovenfabric rich in stretchability is preferred in order to impartstretchability thereto. A mixed knitted fabric formed by mixed knittinga polyester yarn and an elastic yarn is more preferred. Examples of theelastic yarn include a polyurethane yarn, a poly(trimethyleneterephthalate) yarn and a poly(butylene terephthalate) yarn. For a wovenor knitted structure, the fabric is preferably a jacquard woven orknitted fabric to which an uneven shape is imparted as described above,or a knitted fabric such as a smooth knitted fabric or a half tricotknitted fabric provided with protruded portions is preferred. Theknitted or woven fabric may be provided with a resin layer on thesurface as described above.

The fabric of the invention may be used for the entire clothes, or itmay be freely used in a desired site in accordance with the applicationof the clothes. For example, when the fabric is used for swimwear, inparticular, for swimwear for racing, the fabric is preferably used in asurface area of 30% or more of the entire clothes in order to reducewater resistance. The fabric is particularly preferably used in the bustportion, the buttock portion, and the like portion susceptible to aflowing water resistance. Moreover, for example, the fabric ispreferably used in the entire portion of the bust and the femoral regionwhen air resistance is applied to clothes such as an athletic shirt andtrunks, and is more preferably used for the entire clothes.

The fabric of the present invention shows a decreased resistance towater and air even when fluid flow directions are variously changed. Thefabric is therefore appropriately used for sportswear for track andfield events, skiing, particularly for ski jumping racing. The fabric isnot restricted to these applications alone.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is specifically explained below by makingreference to examples.

Evaluations in the present invention are made by the following methods.

(1) Compression Ratio of Micro-Area in a Surface of a Fabric and a Resin

Using a microcompression testing machine (manufactured by ShimadzuCorporation, and the like), measurements are made under the followingconditions: a maximum load of 98 mN; a minimum load of 4.9 mN; adiameter of a probe of 500 μm; and a compression rate of 7.7 mN/sec.

A sample, 5 cm×5 cm, is allowed to stand still. A protruded portion israndomly selected, and the center of the probe is made to conform to thecenter of the width of the protruded portion, followed by making ameasurement. The measurement site is changed, and a measurement is made(n=10). An average of the measured values is determined (for a fabrichaving no protruded portions, measurement sites are randomly selected).The compression ratio (EMC) of micro-area in a surface is determinedfrom the following formula:compression ratio (%) of micro-area in a surface=(L1/d)×100wherein L1 (μm)=(displacement under a maximum load)−(displacement undera minimum load), and d is a diameter (μm) of the probe.

(2) Shape of Protruded Portions

Measurements are made with a three-dimensional shape determinationsystem (trade name of LC 2400, manufactured by Sigma Koki Co., Ltd.). Asample, 5 cm×5 cm, is allowed to stand still so that the sample hasneither curls nor strains. Measurements are made in an area of 3,000μm×3,000 μm or more, at a measurement interval of 20 μm, and data ofheights at respective measurement points are obtained.

(3) Fluid Resistance

Measurements are made in accordance with a method described in Example 1“method of measuring a fluid resistance of a fabric and an apparatustherefor” in Japanese Unexamined Patent Publication (Kokai) No. 7-63749.

An acrylic circular tube 3 cm in diameter and 1.5 m long having abranched tube at a site 30 cm apart from the top is placed at aninclination of 15 degrees as a tilting flow path. Water from a waterline is allowed to flow at a flow rate of 70 liter/min. Twosemispherical silicone rubber-made caps are attached to both ends,respectively, of an aluminum circular tube (apparent specific gravity of0.68 g/cm³) 1.6 cm in diameter and 16 cm long. A sample is wound aroundan adapter which is at one end of the aluminum tube and to which apolyester monofilament yarn 120 cm long having a size of 150 denier (167dtex) has been attached. The aluminum tube is positioned within theacrylic circular tube, and measurements are made.

A push-pull gauge (manufactured by Aiko Engineering Co., Ltd.) is usedas a tension measurement apparatus, and attached to a polyestermonofilament yarn. A sample, 4.5 cm×14.5 cm, is prepared by cutting afabric. The sample is stitched to form a tubular shape. An adapter iscovered with the sample, and an adhesive tape is wound around both endsof the sample to fix the sample.

EXAMPLE 1

A fabric having a pattern of wavy, streaky protruded portions wasprepared with a 28-gauge jacquard knitting machine. A polyester yarncomposed of a poly(ethylene terephthalate) and having a size of 33dtex/36 filaments was supplied in the front yarn guide of the knittingmachine. A polyester yarn composed of a poly(ethylene terephthalate) andhaving a size of 56 dtex/36 filaments was supplied in the middle yarnguide of the knitting machine. A spandex yarn having a size of 44 dtexwas supplied in the back yarn guide of the knitting machine (blendingratio: 40% by weight in the front portion; 48% by weight in the middleportion; and 12% by weight in the back portion). The fabric wasconventionally finished, and the shape of protruded portions of thekitted fabric was measured. The following results were then obtained: awidth of 350 μm; a height of 450 μm; a space of 1,800 μm (streakyprotruded portions); and a cycle of waviness of 6,500 μm and a width ofwaviness of 1,600 μm.

The compression ratio of micro-area in the fabric surface was 28%.

Measurements of a fluid resistance were made on swimwear having beenprepared from the fabric so that the protruded portions were in parallelto the longitudinal direction of a human body. Table 1 shows theresults. In Table 1, a fluid resistance is a value obtained bysubtracting a tension of 65 g obtained when the fabric was not attachedfrom a measured value when the fabric was attached. The results areshown under the titles of “longitudinal”, “lateral” and “45 degrees”. Inaddition, “longitudinal” herein represents the longitudinal direction ofthe swimwear, that is, it represents a case wherein the direction of thestreaky protruded portions is parallel to the water flow direction;“lateral” herein represents a case wherein the direction of the streakyprotruded portions is vertical to the water flow direction; and “45degrees” herein represents a case wherein the longitudinal direction ofthe fabric makes an angle of 45 degrees with the water flow direction.

It is understood from the results that the fabric obtained in Example 1is a fabric showing a low fluid resistance.

EXAMPLE 2

The jacquard knitted fabric obtained in Example 1 was calendared at 180°C. to give a fabric having streaky protruded portions. Measurements weremade on the fabric in the same manner as in Example 1. Table 1 shows theresults.

The shape of the protruded portions was as follows: a width of 350 μm; aheight of 230 μm; a space of 1,800 μm (streaky protruded portions); anda cycle of waviness of 6,500 μm and a width of waviness of 1,600 μm.

Moreover, the compression ratio of micro-area in the fabric surface was12.5%. The fabric showed a still lower fluid resistance due to thesmoothing effect of the fabric surface.

EXAMPLE 3

A releasing paper having the following pattern of streaky protrudedportions was prepared: a width of 200 μm; a height of 300 μm; and aspace of 650 μm. Using the releasing paper, an uneven film was formedout of a polyurethane resin (prepared by adding 2% by weight of CrisvonAssitor SD 27 to Crisvon NYT-20, both being trade names and manufacturedby DAINIPPON INK AND CHEMICALS, INC.) containing DMF as a solvent, by anautocoater with a clearance of 200 μm. In addition, the film was driedat 80° C. for 2 minutes.

The 300 μm thick film thus obtained showed a surface compression ratioof 45%.

The uneven film thus obtained was laminated to a 32-gauge two-way tricotknitted fabric formed out of 76% by weight of a polyester yarn that wascomposed of poly(ethylene terephthalate) and had a size of 56 dtex/36filaments and 24% by weight of a spandex yarn that had a size of 44 dtexto give a fabric having a surface layer of an elastic layer. Inaddition, during lamination, the streaky unevenness was made to conformto the longitudinal direction of the knitted fabric, and both werebonded with an adhesive (a solution of Crisvon 4070 (trade name,manufactured by DAINIPPON INK AND CHEMICALS, INC.) in toluene).

The fabric having a surface layer of an elastic layer was used as asample, and measurements were made in the same manner as in Example 1.Table 1 shows the results.

The shape of the protruded portions was as follows: a width of 210 μm; aheight of 250 μm; and a space of 650 μm (streaky protruded portions).Moreover, the fabric showed a compression ratio of micro-area in thefabric surface of 25%, a low fluid resistance, and sufficientstretchability.

EXAMPLE 4

A fabric having a surface layer of an elastic layer was prepared in thesame manner as in Example 3 except that a releasing paper having apattern of micro-protruded portions that had waviness in the directionvertical to the streaky protruded portions with a cycle of 10,000 μm anda width of 1,200 μm was used. The fabric having a surface layer of anelastic layer was used as a sample, and measurements were made in thesame manner as in Example 1. Table 1 shows the results.

The shape of the protruded portions was as follows: a width of 210 μm; aheight of 250 μm; a space of 650 μm (streaky protruded portions); and acycle of waviness of 10,000 μm and a width of waviness of 1,200 μm.

The fabric showed a compression ratio of micro-area in the fabricsurface of 36%, a very small flowing water resistance in any of theflowing directions in the longitudinal, lateral and 45 degreesdirections, and sufficient stretchability.

EXAMPLE 5

A fabric having a surface layer of an elastic layer was prepared in thesame manner as in Example 4 except that a releasing paper having apattern of micro-protruded portions that had, in the direction verticalto the streaky protruded portions, a height of 50 μm and a space of1,350 μm was used. The fabric having a surface layer of an elastic layerwas used as a sample, and measurements were made in the same manner asin Example

1. Table 1 Shows the Results.

The shape of the protruded portions was as follows: a width of 210 μm; aheight of 250 μm; a space of 650 μm (streaky protruded portions); acycle of waviness of 10,000 μm and a width of waviness of 1,200 μm; andmicro-unevenness in the direction vertical to the streaky protrudedportions with a height of 50 μm and a space of 1,350 μm. The fabricshowed a compression ratio of micro-area in the fabric surface of 42%, avery small flowing water resistance in any of the flowing directions inthe longitudinal, lateral and 45 degrees directions, and sufficientstretchability.

EXAMPLE 6

The two-way tricot knitted fabric used in Example 3 was embossed with aprotruded portion pattern having a width of protruded portions of 200μm, a height of 150 μm and a space of 550 μm to give a fabric. Table 1shows the results of evaluating the fabric thus obtained.

The shape of the fabric was as follows: a width of 200 μm; a height of90 μm; and a space of 550 μm (streaky protruded portions). Moreover, thefabric showed a compression ratio of micro-area in the fabric surface of8.5%.

EXAMPLE 7

The two-way tricot knitted fabric used in Example 3 was embossed to givea fabric. The pattern of the emboss roll used for embossing was the sameprotruded pattern having waviness as that of the releasing paper used inExample 4 except that the protruded portions were dotted, and had awidth of 250 μm, a length of 400 μm and a space in the longitudinaldirection of 500 μm.

Table 1 shows the results of evaluating the fabric thus obtained.

The shape of the protruded portions was as follows: a width of 210 μm; aheight of 250 μm; a space of 650 μm (streaky dots); and a cycle ofwaviness of 10,000 μm and a width of waviness of 1,200 μm. Moreover, thefabric showed a compression ratio of micro-area in the fabric surface of40%, a very small flowing water resistance in any of the flowingdirections in the longitudinal, lateral and 45 degrees directions, andsufficient stretchability.

COMPARATIVE EXAMPLE 1

A fabric having streaky protruded portions was obtained in the samemanner as in Example 1 except that the jacquard knitted fabric havingbeen used in Example 1 was used, and that the pattern of protrudedportions was altered. Table 1 shows the results of evaluating the fabricthus obtained.

The shape of the protruded portions was as follows: a width of 3,000 μm;a height of 300 μm; a space of 3,000 μm (streaky protruded portions);and a cycle of waviness of 10,000 μm and a width of waviness of 4,000μm. Moreover, the fabric showed a compression ratio of micro-area in thefabric surface of 7%.

COMPARATIVE EXAMPLE 2

The tricot knitted fabric used in Example 3 was not treated, and used asa sample. Table 1 shows the results of evaluating the sample.

COMPARATIVE EXAMPLE 3

The tricot knitted fabric used in Example 3 was treated in the samemanner as in Example 3 with a releasing paper without unevenness to givea fabric. Table 1 shows the results of evaluating the fabric.

COMPARATIVE EXAMPLE 4

A fabric was obtained in the same manner as in Example 6 except that theprotruded portions had a width of 650 μm, a height of 200 μm and a spaceof 800 μm. Table 1 shows the results of evaluating the fabric thusobtained.

COMPARATIVE EXAMPLE 5

A fabric was obtained in the same manner as in Example 3 except that apolyurethane film 300 μm thick showing a compression ratio of 97% wasused. Table 1 shows the results of evaluating the fabric thus obtained.

The fabric has remarkable tucking properties, sticks together when thefabric was folded, and showed poor handleability.

It is understood from the results in Table 1 that the fabrics of thepresent invention (Examples 1 to 7) show decreased fluid resistance. Incontrast to the fabrics of the invention, it is understood that thefabrics of Comparative Examples 1 to 4 show increased fluid resistanceand that the fabric in Comparative Example 5 shows poor handleability.TABLE 1 Compression Streaky protruded ratio of portions Waviness Surfaceroughness micro-area Fluid resistance (μm) (μm) (μm) in a surface (g)Width*height*space Cycle*width Lo⁺ La⁺ (%) Lo⁺ La⁺ 45 deg⁺ Note Ex. 1250*230*1800 6500*1600 4.4 6.1 28 19 27 24 Ex. 2 350*230*1800 6500*16001.8 2.2 12.5 17 23 22 Ex. 3 210*250*650 — 0.6 4.2 25 22 32 29 Ex. 4210*250*650 10000*1200 0.8 3.2 36 17 22 23 Ex. 5 210*250*650 10000*12001.3 3 42 16 15 14 Unevenness formed in two directions Ex. 6 200*90*550 —0.8 2.5 8.5 23 33 30 Ex. 7 210*250*650 10000*1200 4.7 7.7 40 22 29 28Dotted C. Ex. 1 3000*300*3000 10000*4000 5.5 8 7 38 42 39 C. Ex. 2 — —3.7 2.7 6 40 48 44 C. Ex. 3 — — 1.1 1.8 7 29 32 35 C. Ex. 4 600*150*800— 1.5 1.5 6 36 45 41 C. Ex. 5 150*200*650 — 1.6 4.9 92 18 27 23 Poorhandle- abilityNote:⁺: Lo = Longitudinal, La = Lateral, 45 deg = 45 degrees

INDUSTRIAL APPLICABILITY

The fabric of the present invention shows a decreased resistance to aflow of water and air, and it does so even when fluid flow directionsare variously changed. The fabric of the present invention is thereforeparticularly suited to the field of sportswear for racing, and can beappropriately used for, for example, sportswear for swimwear for racing,sportswear for track and field events and sportswear for skiing, andparticularly for sportswear for ski jumping.

1. A fabric for clothes showing a compression ratio of a micro-area inthe fabric surface on the surface side opposite to a body of from 8 to90%, and having streaky protruded portions on the surface side oppositeto body.
 2. The fabric according to claim 1, wherein the protrudedportions have a width of 100 to 2,500 μm, and a height of 30 to 300% ofthe width of the protruded portions.
 3. The fabric according to claim 1,wherein the fabric has, on the surface side opposite to body, wavy,streaky protruded portions in one direction.
 4. The fabric according toclaim 3, wherein protruded portions in the wavy, streaky protrudedportions have a width of 100 to 2,500 μm, a height of 15 to 300% of thewidth of the protruded portions, a cycle of waviness of 2,000 to 20,000μm, and a width of the waviness of 5 to 50% of the cycle of waviness. 5.The fabric according to any one of claims 1 to 4, wherein the streakyprotruded portion has micro-unevenness having a depth of 80% or less ofthe height of the protruded portion in the direction vertical to thestreaky protruded portion.
 6. The fabric according to any one of claims1 to 5, wherein the average deviation of a surface roughness in thedirection parallel to the streaky protruded portions is 5 μm or less,and the average deviation of a surface roughness in the directionvertical to the streaky protruded portions is 8 μm or less.
 7. Thefabric according to any one of claims 1 to 6, wherein the fabric iscomposed of a polyester yarn and an elastic yarn.
 8. The fabricaccording to claim 7, wherein the fabric is a jacquard knitted fabric.9. The fabric according to any one of claims 1 to 7, wherein the fabrichas a surface layer of an elastic layer on the surface side, opposite toa body, of the fabric.
 10. Sportswear for racing formed, in at least aportion thereof, out of the fabric according to any one of claims 1 to9.
 11. Swimwear formed, in at least a portion thereof, out of the fabricaccording to any one of claims 1 to
 9. 12. The swimwear according toclaim 11, wherein the fabric has streaky protruded portions arranged inthe longitudinal direction of a human body.